package org.magneton.support.util;

import org.magneton.foundation.MoreStrings;

import javax.servlet.http.HttpServletRequest;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Objects;

/**
 * 获取IP方法
 * 
 * @author ruoyi
 */
public class IpUtils {

	public final static String REGX_0_255 = "(25[0-5]|2[0-4]\\d|1\\d{2}|[1-9]\\d|\\d)";

	/**
	 * 匹配 ip
	 */
	public final static String REGX_IP = "((" + REGX_0_255 + "\\.){3}" + REGX_0_255 + ")";

	/**
	 * 匹配 ip 通配符
	 */
	public final static String REGX_IP_WILDCARD = "(((\\*\\.){3}\\*)|(" + REGX_0_255 + "(\\.\\*){3})|(" + REGX_0_255
			+ "\\." + REGX_0_255 + ")(\\.\\*){2}" + "|((" + REGX_0_255 + "\\.){3}\\*))";

	/**
	 * 匹配网段
	 */
	public final static String REGX_IP_SEG = "(" + REGX_IP + "\\-" + REGX_IP + ")";

	/**
	 * 未知
	 */
	public static final String UNKNOWN = "unknown";

	/**
	 * 获取客户端IP
	 * @return IP地址
	 */
	public static String getIpAddr() {
		return getIpAddr(ServletUtils.getRequest());
	}

	/**
	 * 获取客户端IP
	 * @param request 请求对象
	 * @return IP地址
	 */
	public static String getIpAddr(HttpServletRequest request) {
		if (request == null) {
			return UNKNOWN;
		}
		String ip = request.getHeader("x-forwarded-for");
		if (ip == null || ip.isEmpty() || UNKNOWN.equalsIgnoreCase(ip)) {
			ip = request.getHeader("Proxy-Client-IP");
		}
		if (ip == null || ip.isEmpty() || UNKNOWN.equalsIgnoreCase(ip)) {
			ip = request.getHeader("X-Forwarded-For");
		}
		if (ip == null || ip.isEmpty() || UNKNOWN.equalsIgnoreCase(ip)) {
			ip = request.getHeader("WL-Proxy-Client-IP");
		}
		if (ip == null || ip.isEmpty() || UNKNOWN.equalsIgnoreCase(ip)) {
			ip = request.getHeader("X-Real-IP");
		}

		if (ip == null || ip.isEmpty() || UNKNOWN.equalsIgnoreCase(ip)) {
			ip = request.getRemoteAddr();
		}

		return "0:0:0:0:0:0:0:1".equals(ip) ? "127.0.0.1" : getMultistageReverseProxyIp(ip);
	}

	/**
	 * 检查是否为内部IP地址
	 * @param ip IP地址
	 * @return 结果
	 */
	public static boolean internalIp(String ip) {
		byte[] addr = textToNumericFormatV4(ip);
		return internalIp(addr) || "127.0.0.1".equals(ip);
	}

	/**
	 * 检查是否为内部IP地址
	 * @param addr byte地址
	 * @return 结果
	 */
	private static boolean internalIp(byte[] addr) {
		if (Objects.isNull(addr) || addr.length < 2) {
			return true;
		}
		final byte b0 = addr[0];
		final byte b1 = addr[1];
		// 10.x.x.x/8
		final byte section1 = 0x0A;
		// 172.16.x.x/12
		final byte section2 = (byte) 0xAC;
		final byte section3 = (byte) 0x10;
		final byte section4 = (byte) 0x1F;
		// 192.168.x.x/16
		final byte section5 = (byte) 0xC0;
		final byte section6 = (byte) 0xA8;
		switch (b0) {
		case section1:
			return true;
		case section2:
			if (b1 >= section3 && b1 <= section4) {
				return true;
			}
		case section5:
			if (b1 == section6) {
				return true;
			}
		default:
			return false;
		}
	}

	/**
	 * 将IPv4地址转换成字节
	 * @param text IPv4地址
	 * @return byte 字节
	 */
	public static byte[] textToNumericFormatV4(String text) {
		if (text.isEmpty()) {
			return null;
		}

		byte[] bytes = new byte[4];
		String[] elements = text.split("\\.", -1);
		try {
			long l;
			int i;
			switch (elements.length) {
			case 1:
				l = Long.parseLong(elements[0]);
				if ((l < 0L) || (l > 4294967295L)) {
					return null;
				}
				bytes[0] = (byte) (int) (l >> 24 & 0xFF);
				bytes[1] = (byte) (int) ((l & 0xFFFFFF) >> 16 & 0xFF);
				bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
				bytes[3] = (byte) (int) (l & 0xFF);
				break;
			case 2:
				l = Integer.parseInt(elements[0]);
				if ((l < 0L) || (l > 255L)) {
					return null;
				}
				bytes[0] = (byte) (int) (l & 0xFF);
				l = Integer.parseInt(elements[1]);
				if ((l < 0L) || (l > 16777215L)) {
					return null;
				}
				bytes[1] = (byte) (int) (l >> 16 & 0xFF);
				bytes[2] = (byte) (int) ((l & 0xFFFF) >> 8 & 0xFF);
				bytes[3] = (byte) (int) (l & 0xFF);
				break;
			case 3:
				for (i = 0; i < 2; ++i) {
					l = Integer.parseInt(elements[i]);
					if ((l < 0L) || (l > 255L)) {
						return null;
					}
					bytes[i] = (byte) (int) (l & 0xFF);
				}
				l = Integer.parseInt(elements[2]);
				if ((l < 0L) || (l > 65535L)) {
					return null;
				}
				bytes[2] = (byte) (int) (l >> 8 & 0xFF);
				bytes[3] = (byte) (int) (l & 0xFF);
				break;
			case 4:
				for (i = 0; i < 4; ++i) {
					l = Integer.parseInt(elements[i]);
					if ((l < 0L) || (l > 255L)) {
						return null;
					}
					bytes[i] = (byte) (int) (l & 0xFF);
				}
				break;
			default:
				return null;
			}
		}
		catch (NumberFormatException e) {
			return null;
		}
		return bytes;
	}

	/**
	 * 获取IP地址
	 * @return 本地IP地址
	 */
	public static String getHostIp() {
		try {
			return InetAddress.getLocalHost().getHostAddress();
		}
		catch (UnknownHostException e) {
			// ignore
		}
		return "127.0.0.1";
	}

	/**
	 * 获取主机名
	 * @return 本地主机名
	 */
	public static String getHostName() {
		try {
			return InetAddress.getLocalHost().getHostName();
		}
		catch (UnknownHostException e) {
			// ignore
		}
		return "未知";
	}

	/**
	 * 从多级反向代理中获得第一个非unknown IP地址
	 * @param ip 获得的IP地址
	 * @return 第一个非unknown IP地址
	 */
	public static String getMultistageReverseProxyIp(String ip) {
		// 多级反向代理检测
		if (ip != null && ip.indexOf(",") > 0) {
			final String[] ips = ip.trim().split(",");
			for (String subIp : ips) {
				if (!isUnknown(subIp)) {
					ip = subIp;
					break;
				}
			}
		}
		return MoreStrings.substring(ip, 0, 255);
	}

	/**
	 * 检测给定字符串是否为未知，多用于检测HTTP请求相关
	 * @param checkString 被检测的字符串
	 * @return 是否未知
	 */
	public static boolean isUnknown(String checkString) {
		return MoreStrings.isNullOrBlank(checkString) || "unknown".equalsIgnoreCase(checkString);
	}

	/**
	 * 是否为IP
	 */
	public static boolean isIp(String ip) {
		return !MoreStrings.isNullOrBlank(ip) && ip.matches(REGX_IP);
	}

	/**
	 * 是否为IP，或 *为间隔的通配符地址
	 */
	public static boolean isIpWildCard(String ip) {
		return !MoreStrings.isNullOrBlank(ip) && ip.matches(REGX_IP_WILDCARD);
	}

	/**
	 * 检测参数是否在ip通配符里
	 */
	public static boolean ipIsInWildCardNoCheck(String ipWildCard, String ip) {
		String[] s1 = ipWildCard.split("\\.");
		String[] s2 = ip.split("\\.");
		boolean isMatchedSeg = true;
		for (int i = 0; i < s1.length && !"*".equals(s1[i]); i++) {
			if (!s1[i].equals(s2[i])) {
				isMatchedSeg = false;
				break;
			}
		}
		return isMatchedSeg;
	}

	/**
	 * 是否为特定格式如:“10.10.10.1-10.10.10.99”的ip段字符串
	 */
	public static boolean isIpSegment(String ipSeg) {
		return !MoreStrings.isNullOrBlank(ipSeg) && ipSeg.matches(REGX_IP_SEG);
	}

	/**
	 * 判断ip是否在指定网段中
	 */
	public static boolean ipIsInNetNoCheck(String iparea, String ip) {
		int idx = iparea.indexOf('-');
		String[] sips = iparea.substring(0, idx).split("\\.");
		String[] sipe = iparea.substring(idx + 1).split("\\.");
		String[] sipt = ip.split("\\.");
		long ips = 0L, ipe = 0L, ipt = 0L;
		for (int i = 0; i < 4; ++i) {
			ips = ips << 8 | Integer.parseInt(sips[i]);
			ipe = ipe << 8 | Integer.parseInt(sipe[i]);
			ipt = ipt << 8 | Integer.parseInt(sipt[i]);
		}
		if (ips > ipe) {
			long t = ips;
			ips = ipe;
			ipe = t;
		}
		return ips <= ipt && ipt <= ipe;
	}

	/**
	 * 校验ip是否符合过滤串规则
	 * @param filter 过滤IP列表,支持后缀'*'通配,支持网段如:`10.10.10.1-10.10.10.99`
	 * @param ip 校验IP地址
	 * @return boolean 结果
	 */
	public static boolean isMatchedIp(String filter, String ip) {
		if (MoreStrings.isNullOrBlank(filter) || MoreStrings.isNullOrBlank(ip)) {
			return false;
		}
		String[] ips = filter.split(";");
		for (String iStr : ips) {
			if (isIp(iStr) && iStr.equals(ip)) {
				return true;
			}
			else if (isIpWildCard(iStr) && ipIsInWildCardNoCheck(iStr, ip)) {
				return true;
			}
			else if (isIpSegment(iStr) && ipIsInNetNoCheck(iStr, ip)) {
				return true;
			}
		}
		return false;
	}

}